Single sheet presses



1965 E. c. MILLS 3,202,089

SINGLE SHEET PRESSES Filed June 11, 1964 4 Sheets-Sheet 1 INVEN TORByuleMua fi:

45 PM, ATTORNEY;

1955 E. c. MILLS 3,202,089

SINGLE SHEET PRESSES Filed June 11, 1964 4 Sheets-Sheet 4 Fig.5. 3

20 3e L l 42 iiiiii 4o 39 35 -37 35 33; i i l INVENTOR 4% WM ATTORNEY 5tures.

United States Patent 0 3,202,099 SINGLE Si'lllET PRESfiES Edward CecilMills, Clifton, Bristol, England, assignor to Western Board MillsLimited, South Wales, a British company Filed June 11, 196%, Ser. No.374,497 Claims priority, application Great Britain, .ilune 17, 1963,24,ti78/63 6 Claims. (@l. lull-214) This invention relates to singlesheet presses as used in the production of board and other fibrous sheetmaterial.

There are a number of problems involved in the construction of singlesheet presses, such as the need to provide, for maintenance purposes, asmuch separation or daylight as possible between the press platen and theco acting member opposed thereto, whilst reducing as much as possiblethe actual working stroke of the press. Another problem is that ofproviding substantially uniform loading over the whole area of theplaten whilst keeping the pressure applying equipment simple thoughreliable in character and economical to install and maintain, using theminimum force to move the platen quickly to the pressureapplyingposition.

Solutions of the above named and other problems are provided by animproved single sheet press according to this invention, which embodiesa number of useful fea- For instance, one object of the invention is toprovide a press which operates economically and accordingly the presentinvention provides a single sheet press which comprises a frame having astationary press head; a platen mounted for vertical movement beneathsaid press head and adapted to be loaded with sheet material to bepressed, fluid pressure means adapted to lift said platen toward saidpress head to apply pressure to sheet material interposed between saidplaten and said head and means to ensure parallel movement of the loadedplaten as it is raised to the pressure applying position.

Another object of the present invention is to ensure a parallel movementof the loaded platen as it is raised to the pressure-applying position.To this end the platen may be suspended at its opposite ends on membersof a linkage system which is under the control of a single fluidcylinder means.

Further objects of the present invention are to increase the capacity ofthe press so far as concerns the size of material which can be handled,by making the press of sec: tional form, and to facilitate the initialassembling and replacement of the fluid cylinder units which applypressure to the platen. Accordingly it is preferred to employ a pressframe of sectional form, in which case the press head surface onto whichthe platen presses sheet material loaded thereon is constituted by thealigned roofs of tunnel openings in a plurality of laterally adjacentunit sections, a single platen being used within the daylight gapprovided by the tunnels of the collateral unit sections.

The need to reduce as much as possible the actual working stroke of theplaten--whilst allowing as and when required the lowering of the platento afford ample daylight-has already been referred to, and with thisrequirement in mind the improved press embodies simple stroke adjustmentmeans for the platen.

Another feature of the improved press is that full pressure is notapplied until the platen is pressing the load against the press head.Prior to this application of final pressure provision is made to keepmoving components of a comparatively large number of cylinder units inclose proximity to contact with, though applying little pressure to, theplaten.

A sectional single sheet press embodying the features specificallyreferred to and incorporating means for solving the above mentionedproblems will now be referred ice to, by Way of example, with referenceto the accompanying drawings, but it will be understood that theinvention in some of its various aspects, may be employed, possibly withsome modification, to existing presses.

In the drawings:

FIG. 1 is a diagrammatic front elevation view, partly in section, of thepress according to the invention.

FIG. 2 is a diagrammatic fragmentary end elevation of one of the unitsections of the press.

FIG. 3 is a vertical cross section through a press section, taken alongline lll-lll of FIG. 2.

FIG. 4- is a plan View of two of the cylinder unit assemblies carriedwithin each pressunit section,

FIG. 5 is a Vertical section through one of the fluid cylinder units,

FIG. 6 is a fragmentary sectional view, taken at right angles to FIG. 5,and

FIG. Tis a layout of hydraulic circuitry suitable for a sectional pressconstructed as illustrated in FIGS. 1 to 6.

The improved press diagrammatically illustrated in FIG. 1 comprises fivecollateral unit sections ll, 1A, 1B, 1C and 1D, which structurally areidentical, the form of section 1 being shown by way of examplein FIGSZand 3. The unit section comprises a Welded metal rectangular frame 2with two parallel horizontal plates extending longitudinally andtransversely therethrough, a base plate 3 and a top plate 4 which definethe depth of a transverse through opening 5. These plates 3, 4 are heldagainst defiection by webs 6 disposed between the plates and theopposing floor '7 and roof 8 respectively on the main frame 2. Thesection 1 is parallel-sided, so that a plurality of interchangeablesections, such as the five shown in FIG. 1, may be clamped together withthe side faces in abutment, long bolts 9 passing through eyed lugs illat the ends of the sections and long bolts 9A passing through guidetubes 11 provided centrally of. the collateral sections being used forclamping. v

When thus collaterally assembled the through openings 5 of the severalsections l-lD combine to form a single tunnel 12 extending from front torear of the sectional press and as the sections are of identical formthe contiguous base plates 3 and top plates 4 combined to provide asingle solid bed 13 and a firm head 14 for the press.

Within the tunnel 12 is situated a platen 15 of any suitable form. Theplaten 15 is adapted to be suspended within the tunnel 12 by hanging itsopposite ends on rods 16 (at least one near each corner of the press)connected to hell cranks 17 mounted near opposite ends of the press.

Motion is transmitted to said bell cranks l7 and rods 16 to raise andlower the platen 15 by means of further rods 13 pivotably attached toopposite ends of centrally pivoted vertical movement of the platen 1.5during normal working.

Beneath the suspended platen 15, resting on the several bed plates 3 ofthe unit sections, are a number of fluid cylinder units 23, convenientlysix cylinder units in each press section, so that the five-section pressof FIG. 1 employs no less than thirty cylinder units.

When the press sections are assembled the interior of the long tunnel 12is not accessible for easy maintenance or replacement of a cylinder unit23 situated beneath the platen l5 and accordingly apertures, 24 areprovided in the opposite ends of the frame 2 of each section to giveaccess to the through opening 5 of dissection at the level of base plate3; it will usually suffice to have a centrally disposed aperture 24 ateach end of the section. It is then convenient to insert a cylinder unitthe use of high horsepower motors and pumps.

assembly 25 comprising a flat mounting plate 26 carrying three of thecylinder units 23 (FIG. 4) through one of the central apertures 24 andthen bodily and laterally displace said assembly 25 out of line with theaperture to leave a clear way for another assembly.

The three cylinder units 23 forming an assembly 25 re convenientlyconnected in series by flanged connectors 23A so that a fluid lineserving three cylinder units 23 needs only to be connected to a junctionattachment 27 on an end cylinder. Each cylinder unit 23 (FIG. is of asimple sturdy construction and comprises essentially an upwardly-openingpot cylinder 28, and a ram 29 with a conventional form of sealing ring30 at its lower end. It is preferred to use a spherical joint betweenthe ram 29 and the ram cap 31 to ensure good contact with the undersideof the platen 15. A bleed valve 32 (FIG. 6) is provided in each cylinder23. To avoid weakening the Wall of cylinder 28 pressure fluid isadmitted to said cylinder through a port 23A in the thick cylinderfloor. Port 28A communicates with a cross bore 23B in the cylinderfloor, and the cross bores 28B of the three cylinders carried onmounting plate 26 are aligned and interconnected by connectors 25A.

Hydraulic circuitry for a sectional press of the character describedabove can be of a simple character, because of the proposed mode ofoperation of the press. For instance, it has already been mentioned thatthe stroke of the suspended platen may be adjusted to a minimum,consistent with providing just suflicient space to load a board onto theplaten. This loading may be and preferably is effected conventionally,and platen movement during normal working is small. When required, therams 29 of the cylinder units 23 may be fully lowered so that a space ofabout three inches above the platen 15 is made available for inspectionand cleaning purposes.

During normal working, fluid at low pressure may be supplied to thecylinder units which is nevertheless just sufficient to raise all therams 29 so as to maintain contact with the platen 1-5 at all timesthatis, the rams until this position is reached. Contact of the board with tthe press head 14 may be signalled in any suitable manner.

Consequently, the final pressure can be applied without Thus thehydraulic circuitry illustrated in FIG. 7, shows a pump set 33 capableof supplying 37.2 cubic inches per second at a pressure of 5000 lbs. persquare inch, to provide the necessary full pressure, the said pump set33 being associated with two high pressure eight gallon accumulators 34(precharged to 3500 lbs. per square inch) and a pressurised hydraulicoil tank 35 to .240 gallon capacity (average air pressure lbs. persquare inch). Oil under pressure may be supplied, via a twoway valve 36to a main line 37 supplying up to thirty cylinder units 2 3, with 7%inch diameter cylinder bore and 3 inch rarn stroke-a total pressure areaof nearly 2000 square inches.

The platen lift cylinder unit 2'1 is connected via a suitable four-waycontrol valve 38 to the pump and accumulator feed line 41, and exhaustsvia discharge line 39 and non-return valve 4! The sequence of operationis, broadly, the raising of the platen 15 by means of the double-actingcylinder unit 21, which is operated from the accumulators 34 via valve33; follow-up of the platen movement by the rams 29, due to pressure inoil tank change-over movement imparted to the spool of valve 36 when theboard loaded on the platen 15 contacts the press head 14, resulting inthe accumulators 34 discharging pressurised oil into the cylinder units23 to raise the rams 29 thereof and thus apply full pressure to theboard; reverse changeover of valve 36 to exhaust the system; operationof valve 3% to reverse the action of cylinder 21 to lower platen 15 andthus expel oil in cylinder units 23 via valves 36 and thence to tank 35.

Raising and lowering of the platen 15 may be efi'ected rather rapidlyowing to the short stroke of the platen and because the weight of theplaten is substantially counterbalanced by low pressure acting on therams 29. A regulating pressure valve 42 may be placed in the feed line4-1 extending between the accumulators 34 and the platen liftingcylinder 21 so that the most suitable operational pressures may beselected [and applied.

It is to be understood that dimensions and other qualitative values havebeen given simply by way of example and that these and modifications instructure may be made by those skilled in the art within the scope ofthe appended claims.

I claim:

1. A single sheet press comprising a frame having a stationary presshead, a platen mounted for vertical movement beneath said press head andadapted to be loaded with sheet material to be pressed, fluid pressuremeans beneath said platen and adapted to apply pressure to said platento lift said platen toward said press head to apply pressure to sheetmaterial interposed between said platen and said head, means to ensureparallel movement of the loaded platen as it is raised to the pressureapplying position and comprising a linkage system mounted on said frameand supporting said platen at its opposite ends, and a single fluidcylinder means controliing said linkage.

Z. A single sheet press comprising a sectional frame made up of aplurality of laterally adjacent unit sections, and having a stationarypress head, a platen mounted on said frame for vertical movement towardsaid press, the surface of said press head onto which said platenpresses sheet material loaded thereon being constituted by the alignedroofs of tunnel openings in said plurality of laterally adjacent unitsections, a fluid-pressure controlled linkage system supporting the saidplaten so as to lift the loaded platen with a parallel movement until itreaches a pressure-applying position, fluid pressure cylinder unitsbeneath said platen for applying upward pressure to the platen onreaching said pressure applying position, and hydraulic pressure supplymeans coupled to said fluid pressure cylinder units for supplying fluidpressure to said units for applying full pressure to said platen by saidcylinder units.

3. A press as claimed in claim 2, in which each tunnel of said sectionalframe houses a plurality of fluid pressure cylinder units each includinga pressure cylinder to follow up the ascending movement of the platen inreadiness to apply full pressure quickly to the raised platen, and inwhich said supply means causes said fluid pressure units during thisfollow-up movement to apply at least only small pressure to the platen.

4. A press as claimed in claim 2 in which said plurality of fluidpressure cylinder units are in groups, and a common mounting for eachgroup of units on which the group of units is mounted, each frame unitsect-ion having an aperture therein opening into the tunnel therethroughthrough which the groups of units on their common mountings can beinserted into the tunnel.

5. A press as claimed in claim 2 in which a plurality of the fluidpressure cylinder units are aligned, and are hydraulically connected toadjacent units in said plurality, and each has a floor with a cross boreextending diametrically of the unit through the floor and further has aport extending from the cross bore and opening into the interior of thecylinder.

6. A press as claimed in claim 1 in which said single 1,467,201 9/23Sehriver 100--258 fluid cylinder means includes means for adjusting the2,300,339 10/42 Camerota 100-258 Stroke of the piston thereof so as toadjust the stroke 2,446,823 8/48 Grant 100- 258 of the platen. r2,627,289 2/53 Berthe'lsen t 144- 281 References Cited by the ExaminerUNITED STATES PATENTS FOREIGN PATENTS 7,666 10/79 Germany.

10 WALTER A. SOH-EEL, Primary Examiner.

3,681,659 3/63 Francis 100-53 X

1. A SINGLE SHEET PRESS COMPRISING A FRAME HAVING A STATIONARY PRESSHEAD, A PLATEN MOUNTED FOR VERTICAL MOVEMENT BENEATH SAID PRESS HEAD ANDADAPTED TO BE LOADED WITH SHEET MATERIAL TO BE PRESSED, FLUID PRESSUREMEANS BENEATH SAID PLATENT AND ADAPTED TO APPLY PRESSURE TO SAID PLATENTTO LIFT SAID PLATEN TOWARD SAID PRESS HEAD TO APPLY PRESSURE TO SHEETMATERIAL INTERPOSED BETWEEN SAID PLATEN AND SAID HEAD, MEANS TO ENSUREPARALLEL MOVEMENT OF THE LOADED PLATEN AS IT IS RAISED TO THE PRESSUREAPPLYING POSITION AND COMPRISING A LINKAGE SYSTEM